Rap Genius made its name as a website where people could annotate the lyrics of their favourite hip-hop tracks, before raising $15m in venture capital, rebranding as Genius and expanding to other musical genres.

Now the company’s grand plan is emerging as far more than music: Genius has ambitions to become a platform for annotating any website.

“The new functionality lets users add genius.com/ to the beginning of any URL to access a version of the page on Genius. The page is fully annotatable, so users can highlight and annotate any text on the page and view others’ annotations.”

The article points out that some of the sites being annotated – it uses the New York Times as an example – may object to their content being pulled in to Genius’ website.

However, Genius tells Capital that visits to these pages will not cannibalise the source’s traffic or advertising revenues, nor will they be able to annotate any content hidden behind a paywall, as used by a number of prominent news sites.

Genius has not hidden its ambitions to use its annotation platform for much more than music. “We’re trying to make Rap Genius into Everything Genius,” co-founder Mahbod Moghadam told the Guardian in July 2013, after the $15m funding round in October 2012.

That round was provided by venture capital firm Andreessen Horowitz, whose co-founder Marc Andreessen had harboured similar ambitions when he was co-developing the Mosaic web browser that later became Netscape.

“It seemed obvious to us that users would want to annotate all text on the web – our idea was that each web page would be a launchpad for insight and debate about its own contents,” wrote Andreessen in an annotatable blog post on Rap Genius as the funding was announced.

“So we built a feature called “group annotations” right into the browser – and it worked great – all users could comment on any page and discussions quickly ensued. Unfortunately, our implementation at that time required a server to host all the annotations, and we didn’t have the time to properly build that server, which would obviously have had to scale to enormous size. And so we dropped the entire feature.

I often wonder how the Internet would have turned out differently if users had been able to annotate everything – to add new layers of knowledge to all knowledge, on and on, ad infinitum. And so, 20 years later, Rap Genius finally gives us the opportunity to find out.”

Genius has yet to announce when the beta test of its new feature will be opened out to a wider audience, as well as details of how it plans to make money from the platform once it is available to all.